Automatic slack adjusters having adjusting mechanisms are known from EP 01917451 B1, EP 02307757 A1, EP 02352931 B1, EP 0598290 A1, EP 0598290 B1, U.S. Pat. Nos. 7,757,824 B2, 8,215,460 B2, 8,245,820 B2 and WO 02003/083322 A1, for example.
In connection with drum brakes, automatic slack adjusters are known across the industry and are used to control the release clearance between the brake lining and the brake drum. Here, it is the task of automatic adjusting units for slack adjusters to prevent the release clearance between the brake lining and the drum brake from becoming too small or too large. If the gap between the brake lining and the brake drum is too small, increased brake lining wear occurs and, in extreme situations, instances of overheating can furthermore occur. In contrast, an excessive air gap between the brake lining and the brake drum has the effect that the braking force is not transmitted to a sufficient extent to the brake system. Thus, variation in the release clearance has direct effects on the braking performance of the drum brake. Since several drum brakes are usually used on commercial vehicles, e.g. one drum brake being arranged on each wheel, it is essential for safe operation of the vehicle that the release clearance should vary as little as possible between the various drum brakes. If, for example, a release clearance on the right-hand side of an axle were significantly smaller at the brake provided there than on the opposite, left-hand side, the braking action would be different and the vehicle would pull to the right during braking. The release clearance thus has an effect not only on the braking action itself but also on the balancing of the vehicle.
It has proven disadvantageous in the prior art that the release clearance in the case of known principles of operation, e.g. in accordance with the publications indicated at the outset, still fluctuates, in some cases by as much as 50%, despite complex and sophisticated adjusting mechanisms. In the prior art, this problem has hitherto been counteracted by manufacturing the individual components of the adjusting units for the automatic slack adjusters with very tight tolerances, entailing a high outlay in terms of time and money. It is furthermore regarded as disadvantageous in the prior art that the assembly of the, in some cases highly complex, units is an involved process.